Mark & Reil make good points in their posts above.

If you do choose to head up Highway 97, you won't find it to be quite as lonely as the Trans-Siberian Highway... but it will be far less developed and offer far fewer services than any highway route you would find in any of the 50 American states.

You indicated that you have two months to get from Vancouver to Newfoundland. I think that an excursion up to the Yukon (Watson Lake) and back would eat up about 10 days, assuming you ride at a leisurely pace, and you might want to use that time elsewhere along the trans-Canada route.

Keep in mind that apparent distances can be quite deceiving when you are looking at a map of Canada that is displayed using a Mercator or modified Lambert projection, which are the two most common map projections used for road maps. The distance from Vancouver to Newfoundland, via the national parks in the Canadian Rockies and following an all-Canadian route (rather than dipping down under the great lakes) is about 5,000 miles. Heading up to Yukon and then backtracking to not miss the national parks would increase that to nearly 7,000 miles.

My take, which I guess I didn't express well in my first post, is that I don't think there is much "reward" to be gained from making that additional 2,000 mile trek north to Watson Lake. Believe me, you'll see enough wilderness, wildlife, and varied geography via any route across the Rockies, and via the northern route across the Great Lakes.

Reil's suggestion to go touring up Vancouver Island is a good one. The distances are not extreme, and the geography and culture on the island are unique. If you have to make a choice, Vancouver Island is the clear winner over the route up to Watson Lake. If money is not a big concern, you could take a ferry from Vancouver Island up to Prince Rupert, and then start your trek east at the terminus of Highway 16 (the Yellowhead Highway) at Prince Rupert. That would take you through Jasper National Park, and allow for a short diversion down the Icefields Parkway (the highway between Jasper & Banff). But, do research the cost of the ferry to Prince Rupert carefully - it might be a wee bit expensive.

Michael